@oo:100%;@b:#2b2b2b;body{margin:0;padding:0}.box{width:100%;height:100vh;background:#000;margin:auto}.buu{width:100vw;height:20vh;position:absolute;bottom:0}.buu>button{width:20vw;height:6vh;font-weight:bolder;font-size:21px;cursor:pointer;margin-left:3%}.bu2{background:red;color:#fff}.bu3{background:#00f;color:#fff}.bu4{background:#000;color:#fff}.bu5{background:green;color:#fff}